A4934GLPTR-T Allegro Microsystems Inc, A4934GLPTR-T Datasheet - Page 7

• Manufacturer Part Number: A4934GLPTR-T
• Description: IC BLDC DVR 3PHASE 16-ETSSOP
• Manufacturer: Allegro Microsystems Inc

Specifications of A4934GLPTR-T

• Applications: Fan Motor Driver, 3-Phase
• Number Of Outputs: 1
• Current - Output: 500mA
• Voltage - Supply: 8 V ~ 16 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP (0.173", 4.40mm Width) Exposed pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Load: -
• Lead Free Status / RoHS Status: Supplier Unconfirmed, Lead free / RoHS Compliant
• Other names: 620-1382-2

A4934
Startup Oscillator Setting (FC)
Typically, the 50 ms setting is optimum for motors appropriate
for use with the A4934. If the motor does not produce a proper
BEMF signal at startup when power is applied, a longer setting
may be required.
SLEW Setting
For some motors, soft switching will reduce audible noise. The
soft switching function can result in motor stall for some motors,
specifically motors with large inductance that run at higher
speeds. For this situation, there are two potential solutions:
• Limit the motor speed by lowering the maximum demand, by
• Consider the pin-to-pin compatible IC A4941 that allows dis-
Current Limiting
Use of the current limit circuit is not required. If motor resistance
(phase-to-phase) will limit the current below the rating in the
Absolute Maximum table, then simply connect the SENSE pin to
C3
reducing either V
abling of the soft switching function.
Typical Application Circuit; speed adjusted via VBB
R2
V
BB
V
BB
C2
1
2
3
4
5
6
7
8
OUTC
CP1
CP2
VCP
GND
SLEW
PWM
FG
motor
(max) or the PWM duty applied.
A4934
PAD
M
CTAP
SENSE
OUTB
OUTA
CTAP
TEST
GND
VBB
FC
16
15
14
13
12
10
11
9
CTAP
R1
C1
V
BB
D2
Application Information
D1
Three-Phase Sensorless Fan Driver
ground. That is:
• If (V
• If (V
Note: For some motor types, use of the current limit circuit may
prevent proper startup due to the effect of the chopping on the
BEMF voltage appearing on the tri-stated winding.
Layout Notes
• Connect GND pins (5,11) to exposed pad ground area under
• Add thermal vias from exposed pad to bottom side ground
• Place V
• Place sense resistor, (if used), as close to the IC as possible.
mines the current limit setting; recommended range is
167 mΩ < R
package.
plane.
Name
C1
C2,C3
R2
D1
D2
R1
BB
BB
(max) / R
(max) / R
BB
0.18 Ω / 0.25 W
Typical Value
0.1 μF / 25 V
10 μF / 25 V
>1.5 A rated
decoupling capacitor as close to the IC as possible.
S
10 kΩ
17 V
< 250 mΩ.
motor
motor
) < 1.25 A, eliminate R
) > I
VBB supply capacitor, minimum 10 μF,
electrolytic can be used
Charge pump ceramic capacitors
FG pull-up resistor, can be pulled-up to
V
Optional blocking diode for supply reverse
polarity protection
Transient voltage suppressor (TVS)
Current limiting sense resistor, required for
low resistance motors
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
OUT
BB
if required
(max), the choice of R
Description
S
.
S
deter-
7